There are a wide variety of electrical connectors adapted for surface mounting on a printed circuit board. Some such connectors are mounted to one side of the circuit board and include solder tails for surface mounting to contact pads on the side of the board or for insertion into holes in the circuit board for soldering to circuit traces interconnected to the holes. Other such connectors are adapted for mounting along an edge of the circuit board, with solder tails of the terminals engageable with contact pads on one or both sides of the board adjacent the edge. The latter type of connectors commonly are called "edge connectors" and, when the solder tails engage contacts on both sides of the board along the edge, the connectors commonly are called "straddle mount" connectors.
One of the problems encountered with straddle mount connectors is that soft solder paste or cream is removed from vital portions of the board contact pads if there is a sliding engagement between the tails and the pads during positioning of the board and the connector in such a straddle mount condition. In a straddle mount connector system, the board must be inserted in a slot or mouth defined between solder tails engageable with contact pads on both opposite sides of the board in a straddling configuration. Soft solder paste is applied to the contact pads on both sides of the board before the board is inserted into the connector. It is desirable to have a predetermined contact force between the solder tails and the board contact pads, in a direction normal to the board, to provide good electrical contact points. On the other hand, it is desirable to have zero or minimal forces between the solder tails and the contact pads while positioning the solder tails on the contact pads to prevent the soft solder paste from being wiped off of the contact pads which can result in defective solder interfaces or short circuiting between adjacent contact pads.
Various approaches have been made in the connector industry to solve the problems outlined above. For instance, in U.S. Pat. No. 5,160,275, dated Nov. 3, 1992, a straddle mount electrical connector is provided which will not cause removal of a cream solder that has been applied to the circuit board, and which will not flaw the surface of circuit portions on the board. The connector has a resilient arm which undergoes elastic deformation to flex contacts perpendicularly away from the surface of the circuit portions when the circuit board is inserted into the connector. The resilient arm is restored to its original shape when the connector has been correctly fitted on the circuit board, thereby allowing the contacts to contact predetermined circuits. In another embodiment, the resilient arm is replaced by a frame member which is urged into the connector body by the circuit board. This causes the contacts to part perpendicularly from the surface of the circuit portions.
Another example is disclosed in United Kingdom patent application No. 2 242 579 A, published Oct. 2, 1991, which includes latch arms at the ends of a connector housing extending in the same direction as the terminal pins or solder tails with molded protuberances at the outer ends of at least one of the latch arms, apparently to keep the board contact pads from touching the solder tails until the circuit board is fully inserted between the spaced latch members, when the terminal pins are electrically engaged with the contact pads. In the fully inserted position, the protuberances fit into openings in the board.
Most such approaches as described above involve additional expensive connector components, even components which are separate from the connector housing, or expensive integral devices between the connector housing and a specially designed board. This invention is directed to providing an extremely simple and cost effective solution to solving the problems outlined above.